Interpretive Summary: Key pecan insect pests include the pecan weevil, black pecan aphid, and stink bugs. Alternative control measures are needed for management of these pests in organic and conventional farming systems. Our objective was to evaluate the potential of several alternative insecticides including three plant extracts, MBI205 (from eucalyptus), Vintre® and ORSA-003 (both from citrus), and two microbial insecticides Grandevo (based on the bacterium Chromobacterium subtsugae) and the insect-killing fungus, Isaria fumosorosea.
RESULTS: In the laboratory, eucalyptus extract, Vintre, ORSA-003, and C. subtsugae caused aphid mortality. In field tests, combined applications of I. fumosorosea with eucalyplus extract were synergistic and caused up to 82% mortality in black pecan aphids. Also in field tests, Grandevo (C. subtsugae) reduced pecan weevil damage by 55% within the first 3 d, and caused 74.5% corrected mortality within 7 d post-treatment. In the laboratory, C. subtsugae and eucalyptus extract did not cause mortality in the brown stink bug.
CONCLUSION: Applications of the bacteria, C. subtsugae (Grandevo), for suppression of pecan weevil, and eucalyptus extract plus the fungus I. fumosorosea for control of black pecan aphids show promise as alternative insecticides and should be evaluated further.

Technical Abstract:
Key pecan insect pests include the pecan weevil, Curculio caryae, black pecan aphid, Melanocallis caryaefoliae, and stink bugs. Alternative control tactics are needed for management of these pests in organic and conventional systems. Our objective was to evaluate the efficacy of several alternative insecticides including three plant extracts, MBI205 (from eucalyptus), Vintre® and ORSA-003 (both from citrus), and two microbial insecticides Grandevo (based on Chromobacterium subtsugae) and Isaria fumosorosea. In the laboratory, eucalyptus extract, Vintre, ORSA-003, and C. subtsugae caused M. caryaefoliae mortality. In field tests, combined applications of I. fumosorosea with eucalyptus extract were synergistic and caused up to 82% mortality in M. caryaefoliae. Also in field tests, C. subtsugae reduced C. caryae damage by 55% within the first 3 d, and caused 74.5% corrected mortality within 7 d post-treatment. In the laboratory, C. subtsugae and eucalyptus extract did not cause mortality in the brown stink bug, Euschistus servus. Applications of C. subtsugae for suppression of C. caryae, and eucalyptus extract plus I. fumosorosea for control of M. caryaefoliae show promise as alternative insecticides and should be evaluated further.